Gallium nitride semiconductors are useful in, among other things, high power electronic and optoelectronics, such as flat panel displays, light emitting diodes, and laser diodes. While most gallium nitride (“GaN”) materials are produced as thin films, GaN powders have applications as electroluminescent phosphor. The first reported synthesis of GaN powder was described by Johnson, W. C., Parsons, J. B., Crew, M. C., “Nitrogen Compounds of Gallium” J. Phys. Chem., 36, 2651-54 (1932) by flowing ammonia over molten gallium heated between 900-1000° C., which caused the following reaction:2Ga(s)+2NH3(g)→2GaN(s)+3H2(g)
Subsequent research described the efficiency of the above-described process. Pichugin, I. G., Yaskov, D. A., “Preparation of Gallium Nitride,” Inorg. Mater., 6, 1732-34 (1972) reported an experiment that caused a reaction on the surface of gallium melt (also referred herein as “Ga melt”) resulting in the formation of grayish colored GaN. Despite an excess of available ammonia much of the gallium melt remained under the crust of GaN created by the reaction, thus requiring several additional stages in order to achieve full reaction. Moreover, impurities such as residual gallium metal and gallium oxide were present in the as synthesized GaN powder, which adversely affected its optoelectronic properties.